Hiya
You'll find that this happens if you've got a Video card with insufficient memory. If it's more than a couple of years old it may perhaps have only 1MB of video memory.
1MB is insufficent to run at 1024 x 768 in most colour modes.
Just get on down to your nearest PC store and buy a PCI graphics card with 4MB + of memory.
I'm assuming that you don't have an AGP graphics card (which is probably the case) so for goodness sake don't let the people at the store con you into buying one!!
Give me a shout if you need more help.
By the way, if your computer is too much of an old fart you're going to have serious performance problems with FS2002 (if that's what you want to run). Any idea on the spec of your PC? Like memory, CPU speed etc.... you can get all this info from the black and white screens you get when your PC boots up.
Good luck.... . <img src="cool.gif" border="0">